A known fuser includes a heat roller, a nip forming member, and a sliding sheet. The nip forming member and the heat roller sandwich an endless belt therebetween to form a nip portion. The sliding sheet is disposed between a portion of an inner circumferential surface of the endless belt and the nip forming member. The sliding sheet has a surface that contacts a portion of the inner circumferential surface of the endless belt. The surface of the sliding sheet has a plurality of dimples for reducing sliding resistance occurring between the surface of the sliding sheet and the endless belt during rotation of the endless belt. The dimples are aligned in a plurality of lines with respect to one direction. The sliding sheet thus has particular portions each straightly extending along the one direction from one end to the other end of the sliding sheet between the dimple edges.
Lubricant may be applied to the inner circumferential surface of the endless belt. Nevertheless, the particular portions, each of which straightly extend along the one direction from one end to the other end of the sliding sheet between the dimple lines, may cause lubricant to move along the particular portions from the one end toward the other end of the sliding sheet and off edges of the sliding sheet. Because of these particular portions, the sliding sheet might not retain as much lubricant as desired. As a result of the loss of lubricant between the sliding sheet and endless belt, a resistance between the sliding sheet and the inner circumferential surface of the endless belt may increase.